The first TV debate between Alistair Darling and Alex Salmond, the leaders of the pro and anti-independence movements in Scotland, saw Darling come out on top, according to a poll.

An instant ICM poll of viewers for the Guardian said Darling had won the debate by 56% to 44%.

The issue of the currency in an independent Scotland sparked the most heated exchanges.

With barely six weeks left until Scotland votes, Mr Salmond, the Scottish First Minister, markedly refused to say what his ‘Plan B’ would be if Westminster refused to let Scotland continue to use the pound.

Although uncertainty over oil revenue and EU membership was expected to dominate, it was the pound that created fireworks.

As leader of the BetterTogether pro-union campaign, Mr Darling had clearly decided in advance that the uncertainty over a future currency was his best chance of landing blows on an adversary expected to win the contest.

The gloves came off when Mr Darling, the former Chancellor, chose to personally attack the SNP leader's promises on the pound.

He said: “An eight-year-old can tell you what Scotland's capital and flag is. But you can't tell us what Scotland's currency will be.”

Mr Salmond said that the pound was “Scotland's too” and that it was “logical and desirable” for Scotland to continue to use it. “I want what is best for Scotland — keeping the pound,” he said.

In perhaps the most emotional appeal of the debate, the First Minister said: “No one, absolutely no one, will do a better job of running Scotland than the people who live and work in Scotland.”

Mr Salmond's strongest attack came on the issue of democracy. “For more than half of my life, Scotland has been governed by parties we didn't elect at Westminster — and these parties have given us everything from the poll tax to the bedroom tax,” he said.

Mr Darling replied that sometimes having a government you do not support is a feature of all democracies, pointing at Mr Salmond to indicate he had not voted for him as First Minister. “There are times that, for the love of our family and the love of our country, it's sometimes best to say ‘No' — not because we can't, but simply because it is not the best thing to do,” he said.

The two men clashed on finance. Mr Darling insisted the country was better off in the UK.

“Money has flowed both ways over the last 30 years, but in the last 22 years Scotland has spent more than it has put in, so we have benefited from being part of the United Kingdom,” he said.

“We have higher public spending here per head than they do in the rest of the United Kingdom.

“As someone who is fiercely proud of being Scottish I am not unhappy that from time to time we tackle problems in Liverpool, in Manchester, in Norwich, in Newcastle, because as well as being Scottish I regard myself as being part of something bigger.”

Mr Salmond insisted: “In each one of the last 33 years, Scotland has paid more in tax per person than the average of the UK. Over the last five years we have £8bn more into the treasury than we had out of it, in relative terms, that is £1,500 a head for every man, woman and child in Scotland.”

But one audience member said the First Minister had been “snide” in his response.

“Quite honestly Mr Salmond I'm disappointed with you. As a politician of some note some of your remarks have been snide and not very nice.”

Mr Darling said much debate was “characterised by guesswork, blind faith and crossed fingers” from the Yes camp. “If we vote to leave there is no going back.”

Key battlegrounds in the referendum TV tussle

The economy

Darling: “We are far stronger having the best of both worlds by having a strong Scottish Parliament and in addition access to a much bigger market. About 15 per cent of Scotland's tax revenue comes from North Sea oil revenue. We know it's in decline and notoriously volatile.”

Salmond: “Every single country in the world with oil seems to think it is a blessing. You think it is a curse. The volatility of oil has not been a problem for Norway.”

Tax

Salmond: “In the last five years Scottish taxpayers have paid £8bn more into the Treasury than we have got out of it in real terms.

Darling: “In the last 22 years Scotland has spent more than it has brought in, so we have benefited from being part of the Union.”

Can Scotland keep the pound?

Darling: “A currency union is stupidity on stilts. It's like getting a divorce and keeping the same joint bank account. If we leave the UK, we leave the pound. The central bank, the Bank of England, would be in a foreign country, setting our interest rates. How could financial institutions like RBS survive without a central bank?”

Salmond: “We will keep the pound because it is our pound as much as England's pound. England is Scotland's biggest export market, and Scotland is England's second-biggest export market. It is logical and desirable to have a currency union.”

Social justice

Salmond: “There are 30,000 more children in Scotland coming into poverty as a result of cuts in the social security system. How can we build a just society when we have policies imposed on us from Westminster? There are more pandas in Edinburgh Zoo than Tory MPs in Scotland — but we still get a Tory government.

Darling: “I want to build a fair, just society. It is far better to do that when you have got a stronger, bigger economy. The Scottish population is ageing more quickly than the rest of the UK. And at the moment the costs and risks of that fall on the UK.”